1. Field of the Invention
The present invention relates to a collision-detecting device for use in an automotive vehicle, and especially to such a device including a deformable member disposed in front of a reinforcing member of a bumper for detecting a collision with a pedestrian.
2. Description of Related Art
It has been required to detect a type of an object collided with a vehicle. In particular, it is important to detect whether a collided object is a pedestrian. Devices for protecting a collided pedestrian have been proposed and tested for putting them into actual use. For example, a hood of a vehicle is lifted and/or an airbag for protecting a collided pedestrian is operated. However, it is important to accurately detect that a collided object is a pedestrian, not an object other than a pedestrian, to avoid unnecessary operation of the pedestrian-protecting device. If the pedestrian-protecting device is unnecessarily operated when objects other than a pedestrian collide with the vehicle, such operation may be harmful to a driver or a passenger in the vehicle. For example, the lifted hood may be crushed into a passenger compartment when the vehicle hits a hard object such as a concrete wall or a heavy vehicle.
To detect types of objects collided with a vehicle, WO 2005/098384 and JP-A-2006-117157 propose a bumper device having a deformable member disposed in front of a bumper-reinforcing member. A pressure change, due to a collision, in an inner space of the deformable member is detected thereby to detect types of a collided object. Further, the deformable member functions as a cushion for protecting legs of a collided pedestrian. The types of collided objects are detected based on a pressure change in the inner space of the deformable member that is proportional to its volume change caused by a collision. In the conventional device, however, there is a problem that the deformable member may not be designed to properly protect the legs of the collided pedestrian.